A163431 Primes p such that floor(p^3/8) is also prime.

3, 19, 83, 179, 191, 239, 373, 431, 643, 719, 739, 883, 1123, 1151, 1171, 1237, 1283, 1429, 1459, 1669, 1811, 2053, 2083, 2293, 2351, 2437, 2579, 2677, 2687, 2819, 2851, 2879, 3167, 3253, 3491, 3539, 3877, 4051, 4099, 4483, 4549, 4643, 4799, 5087, 5171

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Formula

A163430(n) = floor( a(n)^3/8 ).

Example

a(1)=3 generates (3^3/8=3.375 where 3 is prime.
a(2)=19 generates (19^3/8=857.275 where 857 is prime.

Mathematica

f[n_]:=IntegerPart[(p/2)^3]; lst={}; Do[p=Prime[n]; If[PrimeQ[f[p]], AppendTo[lst, p]], {n, 7!}]; lst

Crossrefs

Sequence in context: A061171 A293561 A240286 * A167242 A089621 A204256

Adjacent sequences: A163428 A163429 A163430 * A163432 A163433 A163434

Keyword

nonn,easy

Author

Vladimir Joseph Stephan Orlovsky, Jul 27 2009

Extensions

Mathematica specific notation removed, comments moved to examples - R. J. Mathar, Sep 17 2009

Status

approved